Variable taper control



3 Sheets-Sheet 1 M. H. ENGLISH VARIABLE TAPER CONTROL Fi led Jan. 23, 1943 I Oct. 10, 1944.

g SIINVENTOR. /7 r /e [0 /1316 75M L. Y AG NT Oct. 10, 1944. M. H. ENGLISH VARIABLE TAPER CONTROL Filed Jan. 23, 1945 3 Sheets-Sheet 2 IN V EN TOR. M r/e 15 /136 AGE @ct m 1944.

M. H. ENGLISH VARIABLE TAPER CONTROL Filed Jan. 23, 1943 I5 Sheets-Sheet 5 INVENTOR BY 7 'r/eh( 619/1196 AGENT Patented Oct. 10, 1944 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates, in general, to an internal grinding machine, and, particularly, to the control means for setting the grinding wheel for taper and cylindrical grinding.

An object of the present invention is to-pro vide improved means for adjusting the control bar of an internal grinding machine, whereby the latter may be readily adapted to grind holes'having both tapered and cylindrical walls and without any appreciable interruption in the'grinding operation. A further object isto provide a manually operated crank for changingthe angle of the control bar for both grinding and wheel dressing operations.

Other objects, features and advantages will be described in the following specification which is descriptive of one embodiment of the invention. It will be understood, however, that the invention includes all modifications within the scope of the appended claims. g

In one of the well known and widely used types of machines for grinding holes, the grinding wheel is carried on an arm which in turn is supported on a rotatable and reciprocable traverse arbor. The cross feed screw of the machine is adapted to engage a control bar carried on the foot of the arm to swing the arm laterally, thus rotating the traverse arbor in its bearings and moving the grinding wheel across an imaginary line coincident with the longitudinal axis of the workpiece.

In this manner, the grinding wheel may be moved sidewise against the wall of the hole being ground. To grind a hole in this manner, that is to say, by simply moving the wheel sidewise into engagement with the Wall of the hole, is known in the art as plunge grinding, whereas to reciprocate or traverse the grinding wheel in the direction of the longitudinal axis of the workpiece while simultaneously feeding the wheel sidewise is termed "traverse grinding. two methods, traverse grinding gives more accurate results and is to be preferred.

In order to traverse grind a cylindrical surface, the control bar is adapted to be set and secured substantially parallel to the longitudinal axis of the workpiece; a cylindrical Wheel or that portion of a wheel which is cylindrical is used and is automatically fed sidewise by engagement of the cross feed means with the control bar during the reciprocatory motion of the wheel. To traverse grind a tapered hole, the control bar is adapted to beset at an angle with respect to the longitudinal axis of the workpiece corresponding to the degree of taper to be ground Of these whereupon the surface of the wheel or a portion thereof which is tapered to correspond to the taper desired, moves substantially parallel to thesurface being ground.

Heretofore, in order to set the control bar at an angle for a taper grind or to change the bar from an angular setting to a zero setting for cylindrical grinding, the operator has beenrequired to virtually cease the grinding operation for an appreciable length of time While the necessary adjustments of the control bar were made. Moreover, these same adjustments had to be made each time it was desired to dress the cylindrical and tapered portions of the grinding wheel using'the dressing tool and holder provided on the machine.

As a consequencaoperato'rs have frequently adopted the-practice of setting the control bar permanently at the required angle for traverse contributed to the poor results obtained by plunge grinding The present invention relates to means for facilitating changing the angular disposition of the control bar so thattraverse grindin technique may be used in the grinding anddressing of both the taperedand cylindrical surfaces of the grinding wheel. I

In the-drawings:

Fig. 1 is a schematic front elevation of a grinding machine particularly adapted to illustrate the present invention.

Fig. 2 is aschematic fragmentary sectional view on line 2-2 of Fig. 1 showing the suspended grinding wheel, control bar and cross feed screw.

Fig. 3 isan enlarged elevation partly in section of the sector and control bar on line 33 of Fig. l.

Fig. 4 is a plan view of the sector and control bar of Fig. 3. I I 4 Fig. 5 is a sectional viewon line 55 of Fig. 4.

Fig. dis a fragmentary sectionalview on-line 66 of Fig. 4.

Referring to the drawings, the internal or hole grinding machine shown in Fig. 1 comprises, in general, a base 10 adapted to support a head I l in which is mounted the grinding unit l2. The base l embodies the cross feed mechanism shown generally at I 4 and a motor [5 having suitable connections l6 therefrom to the cross feed mechanism l4 and grinding unit l2 whereby a cross feed screw H, see Fig. 2, and grinding wheel l8 mounted on the head I 2 are power driven,

The grinding unit or wheel supporting means I2 is fixedly mounted on a horizontal arbor [9 supported at one end to rotate in bearings in the head II, and suitable means indicated generally by the hand lever 20 are provided for manually reciprocating the arbor IS in its bearings whereby the grinding unit and wheel l8 can be moved or traversed toward and away from a suitable workpiece holding chuck 22, see dotted lines in Fig. 1, mounted in the head ll.

A suitable control, indicated at 23, is provided for actuating suitable power means which automatically rotates the arbor I9 in its bearings from its normal position as shown to swing the grinding unit l2 and wheel 18 counterclockwise or to the right as viewed in Fig. 2. In this manner, the grinding wheel may be swung out of the way while the operator is engaged in mounting the workpiece in the chuck or test gauging the size of the hole bing ground or other similar operations.

The arbor 19 may also be rotated by means of the cross feed screw [1 to move the grinding wheel l8 transversely of an imaginary line coincident With the longitudinal axis of the chuck 22. To this end, the cross feed screw l1 carries at its inner end a pivoted anvil 24 adapted to be engaged by a control means comprising a bar 25 mounted on a foot 26 at the lower end of an arm 21 of the grinding unit l2. It will be evident that, as the feed screw I1 is advancedand retracted, either manually or automatically, the arm 21 of the grinding unit l2 will swing to the right or left respectively, see Fig. 2, with the rotation of the arbor I9.

In this manner, means are provided whereby the grinding wheel 18 can be'moved transversely into or from engagement with the Wall of the hole being ground. Moreover, in order to maintain the relationship between'the grinding wheel I8 and the wall of the hole, as effected by substantially continuous contact of the anvil 24 with the control bar 25 while the wheel I8 is being traversed or reciprocated, the control bar 25 is made relatively long, see Fig. 4, so that its periphery will move continuously in engagement with the anvil 24 of the cross feed screw.

For further and more detailed description of the grinding machine thus far described, reference may be had to Patent No. 1,765,787, Bryant, June 24,1930.

It will be apparent that if the hole in the workpiece is to be ground cylindrical, then the longitudinal axis of the control bar 25 must necessarily be arranged substantially parallel to the longitudinal axis of the workpiece so that the cylindrical surface of the grinding wheel will move longitudinally of the workpiece and par. allel to its walls.

If the surface to be ground is conical or tapered, then a grinding wheel having a similarly tapered surface is used and the control bar 25 must be turned at an angle to the longitudinal axis of the workpiece corresponding to the angle of the taper. Thus, as the wheel is traversed back and forth in the hole, the tapered surface of the grinding wheel will move substantially parallel to the tapered wall being ground.

Improved means for supporting the control bar so that it may be displaced angularly with respect to the longitudinal axis of the chuck or workpiece therein comprises a sector 28 pivoted at 29 to the foot 26 beneath the outer extremity thereof and provided with split jaws 30 and 32, see Figs. 3 and 4, adapted to clasp the bar 25 which is clamped therein by a suitable screw bolt 33.

The arcuate end 34 of the sector 28 opposite the pivot pin 29 is held up against the bottom of. the foot 26 by fastening means comprising an apertured plate 35 and a pair of socket bolts 36 which project up through the apertures in the plate 35, through an arcuate slot 31 in the portion 34 of the sector and are screw threaded into the foot 26. The bolts 36 are adapted to be drawn up tight enough to prevent the sector 28 from sagging and binding but not tight enough to prevent the sector from turning freely about its pivot 29.

The improved means for pivoting the sector 28 comprises a crank actuated connecting rod 38 which is threadedly secured at one end in the radially disposed hole of a pin 39 rotatably mounted in a vertically drilled aperture 40 of the sector 28. The opposite end of the connecting rod 38 has a radial flange 42, see Fig. 6, at a suitable distance from the end of the rod and a keyway 43 adapted to accommodate the end of a key or stud screw 44 of a collar 45 which has a diametrically disposed V-shaped key 46 formed on one face. Mounted on the connecting rod 38 between the flange 42 and collar 45 is a semicylindrical sleeve 41 having a plurality of diametric V-shaped grooves in one end, each adapted to accommodate the key 46 of the collar 45 whereby the sleeve 41 may be adjusted with respect to and fixedly secured against rotation on the connecting rod 38. The sleeve 41' is held snugly but resiliently against the shoulder 42 of the rod 38 by a coil compression spring 458 which is carried on the end of the rod 38 between the collar 45 and a second collar 45l secured to the end of the rod. f j

The upper surface 43 of the sleeve "is substantially fiat and provided with a vertical stud or crank pin 49 drilled and threaded axially for a headed screw 50. to project up into an eccentrically disposed aperture 52 of a cylindrical crank pin block 53, the lower face 54 of which constitutes a smooth bearing surface. The aperture 52 is counterbored as at 55 to accommodate the head of the screw 58. 7 Thus, by inserting the crank pin 49 into the eccentric aperture 52 of the crank pin block and securing the two parts together by the headed screw 50 in the manner shown in Fig. 6, the sleeve 41 and crank pin block 53 will be held together so that their respective bearing surfaces 48 and 54 make a snug'slidable fit. s

The crank block 53 is drilled vertically axially as at 56 to receive the reduced end 51 of a shouldered post 58; the shoulders 580 of which provide bearing surfaces for, rotatably supporting the post on a substantially-horizontal flat surface 60 of a bracket 62 whichis secured at its opposite end to the foot 26v of the arm 21 by a bolt 63. The'reduced end -5l of the post extends down through a suitable aperture drilled in theflat surface 68 of the bracket, the crank block 53 being secured to the end 51 by a pin 59. The post 58 has an axially drilled aperture 64 The crank pin is adaptedv to receive the lower end of a crank arm or: rod 55 which is secured to the post 58 by a stud screw 66. The crank rod 85 is supported substantially vertically on the arm 21 by a suitable bracket 61 bolted to the arm 21 and has a handle 68 at its wherein the control bar is substantially parallel to the axis of the chuck for making a cylindrical grind to an angle of substantially 7 for a taper grind.

Suitable means for setting the-control bar at its zero position comprises a zero setting stop for the sector 28 consisting of an adjustable set screw H having a lock nut 12 and threadedly secured in a suitable bracket 13 formed on the foot 26 of the arm 21. The end of the set screw 1| constitutes an abutment for a flat" at one end of the arcuate portion 34 of the sector when the latter is at its zero setting.

Suitable means for setting the sector at an angle for grinding a tapered surface comprises a stop pin 16, see Figs. 4 and 5, having a drive fit or otherwise secured in an aperture in the foot 26 of the arm 21 and adapted to project downwardly into the slot 31 of the sector 28. An adjustable set screw 11 having a lock nut 18 is threadedly secured in a wall 19 which defines the .end of the slot 31 of the sector, one. end of the screw 11 being adapted to project through the wall 19 into the slot. When thesector is pivoted counterclockwise, as seen in Fig. 4, its angular displacement will be limited by engagement of the end of the set screw 11 with the pin '15. By mounting the stop pin 16 in the aperture in the foot 28, the pivotal movement ofthe sector is limited substantially to a predetermined angle which in this instance is substantially 7 or slight variations thereof by adjustment of the set screw 11, but it will be obviousthat more projects radially from the side of the post 58 when the sector or control bar is in its zero or angular position respectively.

In order that the control bar maybe held positively or locked at its zero setting, the crank post 58 is rotatively adjusted with respect to the crank block 53 so that the finger 10 of the post will engage the pin 69 when the crank pin 49 is substantially on dead center or slightly beyond dead center, that is to say the crank pin will be substantially in axial alignment with or swung counterclockwise, as seen in Fig. 4, slightly beyond an imaginary line through the. axis 51.0f the crank block and the pivot pin 39 of the sector 28 when the latter is at its zero setting. The slidable sleeve 41 and coil spring 450 constitute a lost motion construction enabling the crank pin to move to its dead center position after further movement of the connecting rod has been prevented by engagement of the sector 28 with the zero stop 10. Moreover, if the crank pin moves slightly beyond dead center, the force of the compressed spring will positively hold the finger 10 in engagement with the stop pin 69.

Similarly, when the crank handle 68 turned to swing the sector 8 from its zero position shown in the drawings to its angular position, the crank pin moves counterclockwise until the finger Hi strikes the pin 69 in which position the crank pin 49 is again on dead center or rotated slightly beyond dead center and the end of the set screw Tl will be held positively in engagement with the stop pin 16. Any force which acts against the control bar 25 to turn the sector back to its original position acts in a line substantially coincident with the crank pin and connecting rod 38 and thereby tends to hold the finger l0 securely against the pin 69'.

The operation of the device is as follows: When grinding a hole having both a tapered surface and a cylindrical surface, a wheel is used, a portion of which is cylindrical and a portion of which is tapered, the latter corresponding to the taper to be ground. The crank arm 68 may first be turned to a position such that the sector 28 is locked at its zero setting, as shown, the control bar 25 being substantially parallel to the longitudinal axis of the workpiece and in engagement with the anvil 24 of the cross feed screw Ill. The machine is then started, whereupon the operator may, by oscillating the handle 20, traverse the cylindrical part of the wheel in and out of the workpiece while the wheel is being moved transversely either automatically or manually by feed means l4 against the surface being ground. When the operator wishes to dress the cylindrical part of the wheel, he withdraws the wheeel from the workpiece and presents its cylindrical surface to the usual diamond tool (not shown) suitably mounted on the machine frame. During the dressing operation, the control bar 25 continues in engagement with the anvil of the cross feed means so that as the wheel is traversed in engagement with the diamond tool, the periphery of the wheel moves substantially at right angles to the longitudinal axis of the tool, thereby dressing a truly cylindrical surface on the wheel.

After completing the cylindrical grind, the operator may immediately turn the crank handle 6B counterclockwise, as shown by the arrow in Fig. 3, until the finger 10 stops against the pin 59' thus quickly setting and locking the control bar at the angle predetermined by the stop pin 16 and set screw 11 and corresponding to the taper to be ground. The tapered portion of the wheel is then traversed back and. forth in the workpiece until a tapered hole of the desired size is obtained. Moreover, the tapered portion of the wheel may likewise be readily dressed, using the diamond tool and holder provided on the machine in which case the angularity of the control bar 25 guides the periphery of the wheel at a corresponding angle to the longitudinal axis of the dressing tool.

Thus, the preferred traverse grinding technique as distinguished from cylindrical plunge grinding methods may be practiced in grinding bothv cylindrical and tapered surfaces without interruption in the normal operation of the machine. Moreover, the mechanical dressing means provided with the machine may be employed for dressing both the cylindrical and tapered surfaces and wheel without creating any loss in time in adjusting the sector, thus eliminating the unsatisfactory and inaccurate practice of dressing the wheel by hand.

What is claimed is:

1. In a grinding machine, article supporting means; an article grinding wheel; means for supporting said grinding wheel; cross feed means; means carried by said supporting means adapted to engage said cross feed means for controlling the disposition of the grinding wheel with respect to the article during the grinding operation; crank means for actuating said control means; resilient means for locking said crank means in operative position; and means for limiting the actuation of said control means by said crank means.

2. In a grinding machine; a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for supporting and traversing said wheel to and from said chuck; cross feed means in said frame for displacing said wheel laterally with respect to the longitudinal axis of said chuck; control means carried by said wheel supporting and traversing means adapted to engage said cross feed means, said control means comprising a pivoted sector having a slot; means on the wheel supporting means adapted to project into said slot for limiting the pivotal movement of said sector with respect to said wheel supporting means; and crank means constructed and arranged to be readily actuatable by the machine operator without interruption of the grinding operation to pivot and to automatically lock said sector whereby said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof.

3. In a grinding machine, a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for supporting and traversing said wheel in said frame to and from said chuck; cross-feed means in said frame for displacing said Wheel laterally with respect to the longitudinal axis of said chuck; control means carried by said wheel supporting and traversing means adapted to engage said cross feed means, said control means comprising a pivoted sector having a slot; means on the wheel supporting means adapted to project into said slot; an adjustable screw carried by said sector adapted to extend into said slot toengage the projecting means for measuring the angular displacement of said sector with respect to an index point on said supporting means; and crank means for pivoting said sector through an angle measured by the setting of said adjusting screw whereby said wheel is moved to and from said chuck in a path at a corresponding angle to the longitudinal axis of said chuck.

4. In a grinding machine, a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for supporting and traversing said Wheel to and from said chuck; cross feed means in said frame for displacing said wheel laterally with respect to the longitudinal axis of said chuck; an anvil pivotally supported on said cross feed means; control means carried by said wheel supporting and traversing means adapted to engage said an- -vil, said control means comprising a pivoted sector; means on the wheel supporting means for limiting the pivotal movement of said sector with respect to said wheel supporting means; and crank means for pivoting said sector wherer5 by said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof, said crank means comprising a manually actuated crank arm and a connecting rod, said connecting rod being pivotally connected at one end to said sector and at its opposite end to said crank arm.

5. In a grindingmachine, a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for .15 supporting and traversing said wheel to and from trol means carried by said Wheel supporting and traversing means adapted to engage said anvil, said control means comprising a pivoted sector; means on the wheel supporting means for limiting the pivotal movement of said sector with respect to said wheel supporting means; crank means for pivoting said sector whereby said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof, said crank means comprising a manually actuated crank arm and a connecting rod, said connecting rod being pivotally connected at one end to said sector and at its opposite end to said crank arm; and means for supporting said crank arm on said wheel supporting and traversing 5 means.

6. In a grindingmachine, a frame; a workpiece holding chuck mounted in said frame; a

grinding wheel; means carried by said frame for supporting and traversing said wheel to and from '40 said chuck; cross feed means in said frame for displacing said wheel laterally with respect to the longitudinal axis of said chuck; an anvil pivotally supported on said cross feed means; control means carried by said wheel supporting and traversing means adapted to engage said anvil,

said control means comprising a pivoted sector; means on the wheel supporting means for limiting the pivotal movement of said sector with respect to said wheel supporting means; crank means for pivoting said sector whereby said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof, said crank means comprising a manually actuated crank arm and a connecting rod, said connecting rod being pivotally connected at one end to said sector and at its opposite end to said crank arm; and a bracket on said wheel supporting and traversing means for supporting said crank arm, said bracket having means for limiting the rotation of said crank arm.

7. In a grinding machine, a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for supporting and traversing said wheel to and from 5 said chuck; cross feed means in said frame for displacing said wheel laterally with respect to the longitudinal axis of said chuck; an anvil pivotally supported on said cross feed means; control means carried by said wheel supporting and traversing means adapted to engage said anvil,

said control means comprising a pivoted sector; means on the wheel supporting means for limiting the pivotal movement of said sector with respect to said wheel supporting means; crank means for pivoting said sector whereby said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof, said crank means comprising a manually actuated crank arm and a connecting rod, said connecting rod being pivotally connected at one end to said sector and at its opposite end to said crank arm; a projection on said crank arm; and a bracket on said wheel supporting and traversing means for supporting said crank arm, said bracket having a pair of stops, at least one stop being located on said bracket to be engaged by the projection on said crank arm when the crank and connecting rod are substantially on dead center.

8. In a grinding machine, a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for supporting and traversing said wheel to and from said chuck; cross feed means in said frame for displacing said wheel laterally with respect to the longitudinal axis of said chuck; an anvil pivotally supported on said cross feed means; control means carried by said wheel supporting and traversing means adapted to engage said anvil, said control means comprising a pivoted sector; means on the wheel supporting means for limiting the pivotal movement of said sector with respect to said wheel supporting means; crank means for pivoting said sector whereby said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof, said crank means comprising a manually actuated crank arm and a connecting rod, said connecting rod being pivotally connected at one end to said sector and at its opposite end to said crank arm; a projection on said crank arm; and a bracket on said wheel supporting and traversing means for supporting said crank arm, said bracket having a pair of stops located on said bracket to be engaged by the projection of said crank arm when the pivotal movement of said sector is restricted by said limiting means.

9. In a grinding machine, a frame; a workpiece holding chuck mounted in said frame; a grinding wheel; means carried by said frame for supporting and traversing said wheel to and from said chuck; cross feed means in said frame for displacing said wheel laterally with respect to the 1ongitudinal axis of said chuck; an anvil pivotally supported on said cross feed means; control means carried by said wheel supporting and traversing means adapted to engage said anvil, said control means comprising a pivoted sector means on the wheel supporting means for limiting the pivotal movement of said sector with respect to said Wheel supporting means; crank means for pivoting said sector whereby said wheel may move to and from said chuck in a path at an angle to the longitudinal axis thereof, said crank means comprising a manually actuated crank arm having a crank pin; a projection on said crank arm; a connecting rod pivotally connected at one end to said sector; a sleeve on the opposite end of said connecting rod, said sleeve being connected to said crank pin; a bracket on said wheel supporting and traversing means for supporting said crank arm, said bracket having stops adapted to be en aged by the projection on said crank arm for limiting the rotation thereof; and resilient means carried on said connecting rod for resisting the movement of said sleeve thereon when the rotation of said crank arm is resisted by at least one of said stops.

MYRLE H. ENGLISH. 

